In accordance with conventional practice, the operator must loosen and remove at least one and as many as six mounting screws to remove a cutter head from a spindle. He then must place the new cutter head in place and reinstall all of the mounting screws and torque them in place. This requires considerable time, up to 30 minutes, and involves the risk of dropping one of the screws in the coolant pit which would involve even more time. In another currently available system, the cutter is attached to an adapter which makes a much heavier unit that usually requires two hands and may take up to five minutes to change.
In accordance with the tool change system of the present invention, the cutter is held on the spindle by a clamp. When the clamp is released, the operator need only grasp the cutter with one hand and rotate it to a position in which it may be pulled off the spindle. The operator may then slide a new cutter on the spindle and reverse rotate it and re-clamp the new cutter. This entire procedure requires only a few seconds to perform.
More specifically, the spindle has a drive plate on which the cutter is mounted. Drive keys on the drive plate engage slots in the cutter so that the cutter rotates with the drive plate. A clamp bar is provided to clamp the cutter against the drive plate. The cutter is formed with clearances which register with the clamp bar when the cutter is rotated relative to the clamp bar, so that the cutter may be removed from the drive plate. A new cutter is then reverse rotated into a position in which it may be clamped by the clamp bar. A spring holds the clamp bar in its clamping position.
The quick change system also includes a pair of locking fingers which are activated by centrifugal force to maintain the cutter clamped to the drive plate even in the event of failure of the spring which normally holds the clamp bar in its clamping position.
One object of this invention is to provide a cutter quick-change system having the foregoing features.
Another object is to provide a cutter quick-change system which is composed of a relatively few simple parts, is rugged and durable in operation, is fast acting, and is capable of being inexpensively manufactured and assembled.
These and other objects, features and advantages of the invention will become more apparent as the following description proceeds, especially when considered with the accompanying drawings.